Added LD-V1000 HLE device, placeholder SSI-263A HLE device, and promoted Thayer's Quest

[MooglyGuy]

Systems promoted to working

Thayer's Quest (set 1) [Ryan Holtz, Matt Ownby, ld-decode Team]

Clones promoted to working

Thayer's Quest (set 2) [Ryan Holtz, Matt Ownby, ld-decode Team]

-thayers: Added CHD and promoted to working. [Ryan Holtz]

• Fixed periodic IRQ hookup.
• Fixed COP421 clock divisor.
• Switched to LD-V1000 by default and removed LD-PR7820 support for now.
• Switched to using logmacro and shorthand data types.
• Adjusted IRQ triggering and acknowledgement according to schematics.
• Extracted SSI-263 skeleton into its own device using the Votrax SC-01 as a stand-in.

-ldv1000hle: Added an HLE version of the Pioneer LD-V1000 laserdisc player. [Ryan Holtz]

-laserdsc: Added a general-purpose parallel laserdisc interface, to have a common class parent for LD-PR7820. [Ryan Holtz]

-ssi263hle: Added a temporary SSI-263 device which remaps SC-02 phonemes onto the SC-01's phoneme set. [Ryan Holtz]

[cuavas]

Looks pretty reasonable.

In general, you’ve been a bit inconsistent with whether you put the explicit virtual prefix qualifier on overridden virtual member functions in addition to the override suffix qualifier. Yes, override implies virtual, but in MAME we generally explicitly include the virtual qualifier as well.

Also, a non-dealbreaking thing – I noticed you used lowercase integer literal suffixes (e.g. 1u). I tend to prefer uppercase (e.g. 1U) due to the long and long long suffixes being potentially confused for 1 digits if they’re lowercase (1LL is less likely to be confused with 111 than 1ll at a glance). By extension I use uppercase for the unsigned and single precision literal suffixes as well.